MEASUREMENTS OF IN-SITU STRESS IN THE PUSHIHE HYDROPOWER STATION, LIAONING

In-situ stress measurements were made in a survey tunnel using the hollow inclusion stress gauge in order to gain knowledge of the present stress state of the Pushihe hydropower station.A total of five in-situ stress-measuring sites were deployed and many measurements were made at each measuring sites.The calculation and integrated calculation of measurement results from the five sites were performed respectively by using the least squares.The results show that:the maximum principal stress is nearly horizontal and oriented in a N79°W direction,with a stress magnitude of 7.1 MPa.Although the measurement results of different segments of the measuring sites show certain deviations mainly due to the structural conditions of rock masses at different sites,the preferred orientation of the maximum principal stress is relatively prominent.Finally,based on the measurement results,the characteristics of the present stresses in the hinge area of the hydropower station are analyzed and some suggestions for the engineering design are presented.